#include <stdio.h>  
int a[305];  
  
int main() {  
    char s[1005];  
    gets(s);  
    for (int i = 0; i < strlen(s); i++) {  
        if (a[s[i] - '\0'] == 0) {  
            putchar(s[i]);  
            a[s[i] - '\0'] = 1;  
        }  
    }  
    putchar('\n');  
    return 0;  
}  